Various aspects of the present disclosure relate generally to engine testing and more particularly to test facilities for testing engines, which capture waste energy from engine testing operations and transform the captured waste energy into usable energy.
When testing an engine, a load on a shaft of the engine may be simulated through the use of a loading device such as a rotary absorber, electrical generator, pump, or dynamometer. As an illustrative example, a rotary absorber is coupled to the shaft of the engine to supply a variable resistance (i.e., reactionary torque) to the shaft as the engine is operated. The amount of resistance supplied by the rotary absorber is controlled as part of the test operation to simulate the load. As the shaft of the engine turns, power transmitted through the shaft is (ultimately) converted to heat through the application of this resistance.
The manner in which the generated heat is removed from the testing system depends largely on the type of loading device. For instance, in many forms of mechanical rotary absorbers, a coolant carries heat energy away from the rotary absorber. The heated coolant is pumped to an evaporative cooler or some other heat exchanger device, where it is cooled. On the other hand, an electrical rotary absorber, such as an eddy current brake typically requires cooling for the generator windings, which is usually accomplished by liquid heat exchange. As another example, an air dynamometer dissipates heat directly to the atmosphere. As yet another example, an electrical generator or dynamometer produces electricity from shaft rotational energy that is routed to resistor banks.